.303-inch

.303-inch ammunition was the standard round adopted by the British in 1889, for both Land and Naval, and subsequently Air, service. Through it’s various iterations, the Mk. VII Ball ammunition was that in service at the time of the introduction of the Mk. I Vickers. The development of the ammunition was then closely linked to the development of the different weapons and the various roles of the Vickers led to various demands for different types of ammunition, including explosive, tracer, armour piercing and many others. These are all covered below.

Cartridge, SA, Ball, .303-inch, Mk. VII (Mk. 7)

First approved in March, 1910, so was the variant in service at the time the Vickers was adopted. The previous variant, the Mk. VI, was in service with the Maxim but the Vickers was not chambered for it. A number of early manuals make reference to the Mk. VI and comparison with the Mk. VII.

It was approved for Land and Naval service in November, 1910, and extended to Air Service in May, 1919 (although likely to have been used extensively before this date).

It used a cordite propellant. It was originally loaded with one glazedboard disc but this was substituted, in 1933, for strawboard to minimise the danger of fired wads to aircraft armed with .303-inch machine guns.

The muzzle-velocity was 2440 feet per second, with 19½ tons per square inch chamber pressure.

One of the major-issues for aircraft use of the Vickers, by the Royal Flying Corps and Royal Air Force, was the quality of ammunition. A special ‘purple label’ ammunition was issued for practice. They also produced a ‘reduced charge’ variant (Cartridge, SA, Ball, .303-inch, NC, Mark VII.z.RC) to simulate a No. 1 stoppage in training. It was introduced in September, 1918, and marked with a blue band 1-inch wide.

This was marked with a black-coloured annulus before 3rd September, 1918, when it was changed to purple.

There were a number of issues with different manufacturers’ ammunition being used in machine guns.

2. The gun should be adjusted so that the lock should go home clear on the .068 cartridge head gauge, and that there should be a check on the 0.69 gauge, the latter being measured by the insertion of a washer or washers in the connecting rod.

4. C.I.S.A. would give due importance to the decision under (2) in dealing with the repair of machine guns.

D.G.M.D. asks C.I.W. to take the necessary steps to give effect to 1 and 2.

C.S.O.F. reports to D.G.M.D., 8.3.16, that trials have been carried out with O.F. proof of cases. It has always been the custom to prove our own output at a pressure 1 ton higher than service ammunition, to allow for possibly worse conditions in the gun than in our proof gun.

1,000 rounds were fired in the Maxim, with the following clearances and results:-

No. of rounds.

Head clearance.

Casualties.

1,000

.064″

Nil.

1,000

.0665″

Nil.

1,000

.069″

2 partial separations.

1,000

.0715″

1 separation.
6 showing signs.

1,000

.074″

4 partial separations.
8 showing signs.

A repeat trial was then carried out:-

No. of rounds.

Head clearance.

Casualties.

1,000

.065″

Nil.

1,000

.068″

2 showing signs of separation.

1,000

.069″

1 separation.
6 showing signs.

From these results, which were all carried out with lots of cases which had gone successfully through original proof, it is not clear what clearance should be employed with the ton extra pressure, and it is not thought safe to drop the latter. Tentatively, a clearance such that .067 will just touch will be tried, but until the point is settled we may have difficulty in meeting the new regulations.

C.I.W. reports to D.G.M.D., 13.3.16, that the following four deliveries have, after rejection under the old test, been accepted after re-test under new conditions:-

D.D.G.(S) informs D.D.G.(E) that he was told by C.I.W. that the trouble with Kynoch’s was due to faulty brass, but that it was now over. That the trouble with Greenwood and Batley was one of manufacture, and this was now also over. That the trouble with Eley’s still existed, being due very largely to faulty brass. He is of the opinion that it is imperative that immediate steps should be taken to see that none but the best material is obtained by, or supplied to, manufacturers of small arms ammunition.

E.M.2 informs D.D.G.(S), 21.3.16, that he is taking this matter up with Eley Bros., and now that supply of brass and cupro-nickel strip for .303 cartridges has been transferred from the Metal Department to his department the points raised in the preceding Minutes will have his special attention. He has written to all S.A.A. manufacturers drawing their attention to the fact thay they are responsible for the testing of all materials used by them.

Referred to the Munitions Design Committee to note.

ACTION TAKEN-Reported to D.D.G.M.D.(S). Noted by the Committee.

Cartridge, SA, Ball, .303-inch, Mk. VIIz (Mk. 7z)

The ‘z’ indicates the use of nitro-cellulose propellant instead of cordite. It was approved for use in May, 1916, for Land Service.

Cartridge, SA, Ball, .303-inch, Mk. VIIIz (Mk. 8z)

The first boat-tailled ammunition was produced to improve accuracy and stability in flight. It was produced for the Vickers and trialled with 20 specially-produced barrels. The Mk. VIIIz was approved for land service in January, 1938, and became the standard ammunition for use in the Vickers in overhead and indirect fire. It was for sole use in the Vickers but could be used in other weapons in exceptional circumstances where reduced muzzle flash was needed. It was the last variant of the .303-inch ball cartridge.

.303″/.22″ Experimental Machine Gun Short Range Practice Ammunition

A necked-down version of the .303-inch Mk. VII case was used to produce a training sub-calibre round that could be used on 30-yard indoor ranges for training purposes. This came with as a set of cartridges and barrel that could be used in a service gun.

Blank Ammunition

Blank ammunition was used with the Blank Firing Attachments. The use of bulleted or long-necked blank was necessary in the Vickers to avoid No. 3 stoppages. The use of ‘short’ blank was officially restricted but it appears that the availablity of the Mk. V blank for all other weapons meant that it was often used in the Vickers, possibly with amendments to the feedblock.

Summary of Approved Marks of .303-inch Blank Ammunition

Mark No.

Approved

Primer

Case

Type

Remarks

Mark 5 Cordite (also nitrocellulose)

1894

Berdan

Ball type

Crimped

Mark 6 Cordite, mock bullet

1901

Berdan

Ball type, crimped with a mock bullet

Case blackened with brass mock bullet

L Mark 7, wood bulleted

1939

Berdan

Ball type

Uncrimped

Yellow wood bullet

L Mark 9 Z

1955

Berdan

Ball type

Crimped

Machine gun Mark I

1914

Berdan

Solid drawn

Short body (heavily bottlenecked)

Drill and Inspectors

Note: Early cartridges Marks, related to the Mk. 6 Ball ammunition, have been omitted from the list.

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